MUSCLES AND FASCIA OF LOWER EXTREMITY 159 



The posterior interossei abduct the fingers from the 

 middle one; the palmar adduct; the interossei and 

 lumbricales flex the first phalanx and extend the last 

 two. 



Flexion in the fingers. Extension in the fingers. 



First phalanx, by the interossei By the extensor communis. 



and lumbricales. 



Second phalanx, by the flexor By the interossei and lumbri- 



sublimis. cales. 



Third phalanx, by the flexor By the interossei and lumbri- 



profundus. cales. 



When we flex the fingers they tend to approach, due 

 to the lateral ligaments and obliquity of the tendons. 



The palmaris longus makes tense the palmar fascia, 

 feebly flexes the forearm and wrist; all the muscles 

 from the condyle feebly flex the forearm. 



Palmaris brevis wrinkles the skin over the hypothe- 

 nar eminence and protects the ulnar vessels and nerve 

 from pressure when a foreign body is grasped. 



Extension in the thumb is in the plane of abduction 

 of the fingers, and its abduction is a movement forward. 

 The action of its muscles and those of the little finger 

 are indicated by their names; the flexors of the first 

 phalanx in either case also extend the last, as the inter- 

 ossei would. The ulnar extensor and flexor of the 

 carpus are moderators of the thumb extensors. There 

 are three flexors of the wrist (including the palmaris 

 longus) and three extensors, three flexors of the fingers 

 and three extensors, three flexors of the thumb and 

 three extensors. 



THE MUSCLES AND FASCLE OF THE LOWER 

 EXTREMITY 



Fasciae of the Thigh 



The superficial fascia is continuous with that of 

 other parts of the body. 



